Reverse Engineering

HACKVent 2020 – Day 24

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Challenge – Santa’s Secure Data Storage

In order to prevent the leakage of any flags, Santa decided to instruct his elves to implement a secure data storage, which encrypts all entered data before storing it to disk.

According to the paradigm Always implement your own crypto the elves designed a custom hash function for storing user passwords as well as a custom stream cipher, which is used to encrypt the stored data.…

HACKVent 2020 – Day 22

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Challenge – Padawanlock

A new apprentice Elf heard about “Configuration as Code”. When he had to solve the problem to protected a secret he came up with this “very sophisticated padlock”.


Unpacking the .zip archive, we got a 19MB Linux executable.…

HACKVent 2020 – Day 14

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Challenge – Santa’s Special GIFt

Today, you got a strange GIFt from Santa:

You are unsure what it is for. You do happen to have some wood lying around, but the tool seems to be made for metal. You notice how it has a rather strange size.…